There are few therapeutic options open for the treatment of patients with severe rheumatoid arthritis who have failed to respond to gold or who have developed an unacceptable toxicity. In this trial, the comparative efficacy and safety of two drugs widely used in this situation are being compared. D-penicillamine (recently approved by the FDA for treatment of RA) and azathioprine, a cytotoxic drug used widely for the treatment of various connective tissue diseases but not yet approved for rheumatoid arthritis. We are one of 11 cooperating clinics in this trial.